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☑ ☐ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K Annual Report Pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 For the Fiscal Year Ended December 31 , 2020 OR Transition Report Pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 For the transition period from Delaware to Commission File No. 001-35791 Northfield Bancorp , Inc. ( Exact name of registrant as specified in its charter ) ( State or other jurisdiction of incorporation or organization ) 581 Main Street , Woodbridge , New Jersey ( Address of principal executive offices ) ( 732 ) 499-7200 ( Registrant's telephone number , including area code ) Securities Registered Pursuant to Section 12 ( b ) of the Act : 80-0882592 ( I.R.S. Employer Identification No. ) 07095 ( Zip Code ) Title of Each Class Common Stock , par value $ 0.01 per share Trading Symbol NFBK Name of Each Exchange on Which Registered The NASDAQ Stock Market , LLC Securities Registered Pursuant to Section 12 ( g ) of the Act : None ☑ No ☑ Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes ☐ No Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes □ Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes ☑ No ☐ Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( §232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes ☑ No □ Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company , or an emerging growth company . See the definitions of “ large accelerated filer , " " accelerated filer , ” “ smaller reporting company , " and " emerging growth company ” in Rule 12b - 2 of the Exchange Act . Large accelerated filer Non - accelerated filer Emerging growth company ☐ ☐ ☐ Accelerated filer ☑ Smaller reporting company ☐ If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act .